The TOPAS / TDS D system combines the advantages of the passive sampling of badge-type passive samplers with thermal desorption for sample transfer to the gas chromatography system. The large surface and the sampler’s short diffusion path permit high sampling rates. Use of thermal desorption as a sample transfer technique avoids the necessity for time consuming sample preparation and allows low detection limits, since the entire sample can be used for gas chromatography analysis. The system is suitable as a personal dosimeter or environmental monitor.
The outstanding feature of the TOPAS system is its completely new designed desorption gas flow path which is built of a spiral-shaped groove. This offers a great diffusion cross section (5.25 cm²). With this new badge geometry high sampling rates equivalent to 3 L/h for volatile aromatic and halogenated hydrocabons were achieved.
A study is presented in which the TOPAS /TDS D system is compared with active sampling on Tenax tubes for determining emissions of volatile organic compounds from a rubber fl ooring. With both types of sampling, active and passive, the same spectrum of compounds was detected. The sampling rates of TOPAS for these compounds were in the range of 0.5 to 2.5 L/h, so during a 5 h sampling period the total enriched amount allows a secure identification and quantification with a GC-MSD system.
The TOPAS / TDS D system has been developed recently by GERSTEL GmbH & Co. KG and the ICB (Institut für Chemo- u. Biosensorik). The present system is still a prototype, but future development is planned to make the system easier for routine use.
